Male Wister rats weighing 280-310 g were anesthetized and the abdomen was opened. A polyethylene catheter was placed and tied in the bile duct of the left lobes (equivalent to 70% of the liver). 0.2 mL of absolute ethanol was injected for 20-25 sec. This dose of ethanol was based on the finding of cholangiography. The weight of the noninfused lobes increased after surgery and reached a 1.6-fold increase by day 14, with the increased level of the Ki-67 labeling index on day 1. In contrast, the weight of the ethanol-infused lobes decreased to less than 50% of the entire liver weight by day 14. Microscopically, the interlobular bile ducts of the infused lobes on day 1 were destroyed, which was uniformly found in the lobes. However, the portal veins and hepatic arteries were structurally well preserved. Ethanol soaked through Glisson's capsule and destroyed hepatocytes, which were replaced by fibrous tissue and proliferating bile ductules without liver abscess on day 14. Both bile flow and bile acid excretion of the noninfused lobes significantly increased on day 3 and became over twice the original values by day 14. In contrast, these variables decreased dramatically in the infused lobes on day 3 and were nearly zero on day 14.From these observations, we concluded that selective intrahepatic biliary infusion of an optimal dose of ethanol can be performed safely without serious complication, achieving a lobar ablation effect with atrophy and creating contralateral hypertrophy.We used this intervention to treat a major bile leak after bepatobiliary resection. During the procedure, the patient complained about flushing but not pain. CT demonstrated atrophy of the infused hepatic segment without liver abscess and compensatory hypertrophy of the noninfused segmens. Furthermore, we applied this intervention to other three patients and could accomplish purposes without any serious complications.